New 2,6,9-trisubstituted adenines as adenosine receptor antagonists: a preliminary SAR profile

A new series of 2,6,9-trisubstituted adenines (5–14) have been prepared and evaluated in radioligand binding studies for their affinity at the human A1, A2A and A3 adenosine receptors and in adenylyl cyclase experiments for their potency at the human A2B subtype. From this preliminary study the conclusion can be drawn that introduction of bulky chains at the N6 position of 9-propyladenine significantly increased binding affinity at the human A1 and A3 adenosine receptors, while the presence of a chlorine atom at the 2 position resulted in a not univocal effect, depending on the receptor subtype and/or on the substituent present in the N6 position. However, in all cases, the presence in the 2 position of a chlorine atom favoured the interaction with the A2A subtype. These results demonstrated that, although the synthesized compounds were found to be quite inactive at the human A2B subtype, adenine is a useful template for further development of simplified adenosine receptor antagonists with distinct receptor selectivity profiles

Modular Mass Spectrometric Tool for Analysis of Composition and Phosphorylation of Protein Complexes

The combination of high accuracy, sensitivity and speed of single and multiple-stage mass spectrometric analyses enables the collection of comprehensive sets of data containing detailed information about complex biological samples. To achieve these properties, we combined two high-performance matrix-assisted laser desorption ionization mass analyzers in one modular mass spectrometric tool, and applied this tool for dissecting the composition and post-translational modifications of protein complexes. As an example of this approach, we here present studies of the Saccharomyces cerevisiae anaphase-promoting complexes (APC) and elucidation of phosphorylation sites on its components. In general, the modular concept we describe could be useful for assembling mass spectrometers operating with both matrix-assisted laser desorption ionization (MALDI) and electrospray ionization (ESI) ion sources into powerful mass spectrometric tools for the comprehensive analysis of complex biological samples

Characterization of human and rodent native and recombinant adenosine A2B receptors by radioligand binding studies

Adenosine A2B receptors of native human and rodent cell lines were investigated using [3H]PSB-298 [(8-{4-[2-(2-hydroxyethylamino)-2-oxoethoxy]phenyl}-1-propylxanthine] in radioligand binding studies. [3H]PSB-298 showed saturable and reversible binding. It exhibited a KD value of 60 ± 1 nM and limited capacity (Bmax = 3.511 fmol per milligram protein) at recombinant human adenosine A2B receptors expressed in human embryonic kidney cells (HEK-293). The addition of sodium chloride (100 mM) led to a threefold increase in the number of binding sites recognized by the radioligand. The curve of the agonist 5′-N-ethylcarboxamidoadenosine (NECA) was shifted to the right in the presence of NaCl, while the curve of the antagonist PSB-298 was shifted to the left, indicating that PSB-298 may be an inverse agonist at A2B receptors. Adenosine A2B receptors were shown to be the major adenosine A2 receptor subtype on the mouse neuroblastoma x rat glioma hybrid cell line NG108-15 cells. Binding studies at rat INS-1 cells (insulin secreting cell line) demonstrated that [3H]PSB-298 is a selective radioligand for adenosine A2B binding sites in this cell line

Body Mass Index Is Associated with Impaired Semen Characteristics and Reduced Levels of Anti-Müllerian Hormone across a Wide Weight Range

There is still controversy as to how body mass index (BMI) affects male reproduction. We investigated how BMI is associated with semen quality and reproductive hormones in 166 men, including 38 severely obese men. Standard semen analysis and sperm DNA integrity analysis were performed, and blood samples were analysed for reproductive hormones. Adjusted for age and time of abstinence, BMI was negatively associated with sperm concentration (B = -0.088, P = 0.009), total sperm count (B = -0.223, P = 0.001), progressive sperm motility (B = -0.675, P = 0.007), normal sperm morphology (B = -0.078, P = 0.001), and percentage of vital spermatozoa (B = -0.006, P = 0.027). A negative relationship was observed between BMI and total testosterone (B = -0.378, P < 0.001), sex hormone binding globulin (B = -0.572, P < 0.001), inhibin B (B = -3.120, P < 0.001) and anti-Müllerian hormone (AMH) (B = -0.009, P < 0.001). Our findings suggest that high BMI is negatively associated with semen characteristics and serum levels of AMH